Shielded cables are used in environments in which there is a risk of electrical and/or magnetic disturbances occurring. The shield construction, and therewith also the function of the shield, will thus depend on the environment from which the cable shall be protected, i.e. shielded, against.
The simplest shielded cable is a so-called coaxial cable which comprises an insulated conductor or cable part which is surrounded by a shield of spirally-wound wires or a braided shield or screen. The shield is embraced by cable sheathing. The effectiveness of the shield can be further enhanced by placing metal foil between said cable part and the shield and/or between the shield and the cable sheathing.
When shielding cables by means of spirally-wound wires, it may be difficult to maintain a sufficient tightness or compactness of the shield when bending the cable for instance, since bending of the cable will cause the shield wires to slide apart on the outer surface of the cable bend. The shielding function is thus impaired at these locations, which is naturally a disadvantage.
Braided shields are comprised of a large number of wires which are placed in accordance with a given pattern. Such shields are encumbered with many manufacturing drawbacks. One of the main drawbacks resides in difficulties in achieving continuous production, as a result of the necessity to stop production in order to effect requisite wire changes. In addition, braiding is a relatively slow process and is therefore usually carried out in a separate production step.
Another drawback resides in connecting the braiding. After having stripped the cable, a sleeve is pressed in beneath the braiding when making a crimp connection of some similar connection. Because of the configuration of the braiding this may be difficult to achieve at times, among other things due to difficulty in inserting the sleeve to the shield.
Another drawback with braided shields is that connection of the shield to an electric contact is effected separately. When stripping the cable, the braided shield is loosened from said cable part or parts and then cut and shaped into a separate conductor. This task is both difficult and time-consuming and there is also a risk that the cable part or cable parts will be cut and therewith damaged.